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(No Model.) 3 Sheets-Sheet 1.

W. G. BARNEY.

PNEUMATIC INTERMITTENT CIRCUIT CLOSER.

No. 388,242. Patented Aug. 21, 1888..

WWI/beam (June whet 3 Sheets Sheet 2. W. O. BARNEY.

4 RMITTENT CIRCUIT CLOSER.

Patented Aug. 21, 1888.

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(No Model.) 3 Sheets-Sheet 3.

W. G. BARNEY.

PNEUMATIC INTERMITTENT GIRGUIT CLOSER. No. 388,242. Patented Aug. 21,1888.

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IVILLIAM CHASE BARNEY, OF NEW YORK, N. Y., ASSIGNOR TO JOSIAH O. BEIFF,OF SAME PLACE.

PNEUMATIC INTERMITTENT CIRCUIT-=GLOSER.

SPECIFICATION forming'part of Letters Patent No. 388,242, dated August21, 1888.

A pplieation filed February 7,1887.

T0 aZZ whom it may concern:

Be it known that 1, WILLIAM Cruse BAR- NEY, of the city and State of NewYork, have invented a Pneumatic Intermittent (lircuit- Closer, of whichthe following is a specification.

In my application for an improvement in telephone transmitters, filedJanuary 18,1886, Serial No. 188,813, for which a patent, No. 357,359,was issued on February 8, 1887, I described several combinations of atympan with electrodes situated in an air-chamber having an entrance andexit for the air-waves, so that the air-waves act first on one side ofthe tympan and then on the opposite side of the same tympan. In thatarrangement the tympan on which is one electrode acts upon only oneother electrode. In my presentinvention the tympan which is connected toone pole of the battery is placed between two electrodes electricallyconnected to the other pole of the battery and arranged to be vibratedbetween these two electrodes, and to make contacts alternately on eachof these electrodes, in this manner closing and opening the circuittwice as rapidly as when the tympan makes contacts on only one electrodeon one side of it.

Figure 1, in accompanying drawings, represents a mid-horizontal section.Fig. 2 is an elevation of the tympan and a section of the case. Fig. 3shows the connections of the battery, induction-coil, electrodes,telephone, and earth.

In a block of wood, Fig. 1, or other suitable material, A A, there is apassageway, B B B B, having an entrance with a mouth-piece, M, and anexit at E on one side of the block or at any other convenient place. Atympan, T, is placed in the air-chamber B B B B, so that it will lie atan acute angle with the entrance hole M. The frame F, holding thetympan, closes the air-chamber B B B B at the top, bottom, and side nearto the entranceM, leaving a passage-way, B B B B, open at the backthereof, so that the air-waves entering the mouth-piece M fall upon thetympan T, and pass around said tympan and find their exit at the hole E.

The tympau T is held in a square frame, F. One side of this frame is inclose contact with Serial No. 226,851. (No model.)

the inside of the case near to the opening at M, and this frame restsfirmly on the inside of the bottom, and the top of the frame is in closecontact with the inside of the top of the case, leaving the passageway BB B B for the air, after entering through the hole M, to pass around theframe, holding the tympan, and then pass out of the case at E.

The bridges D D are at opposite sides ofthe tympan T, and connected attheir ends to the frame F, and at the middle of the bridges areadjusting-screws P P, forming at their ends electrodes. These screws areopposite to each other and to the intervening electrodes, 0 O, in thetympan; but these electrodes do not touch each other. The electrodes 0 Oon the tympan are connected to one pole of a battery, and the electrodesP P are connected to the other pole of the same battery, or to theprimary wire of an inductioncoil, as illustrated in the diagram, Fig. 3.

In Fig. 2, F is the frame; T,the tympan, which is secured to the frameby the ring It by means of screws. 0 is a small disk,of any hardmaterial which will conduct electricity, attached to the center of thetympan, and is connected by a conductor to one pole of a battery,G, theother pole being connected to one end of the primary wire oi'aninduction-coil. Abridge, D, spanning the center of the tympan, isattached to the frame at its two ends by two supports, and at the centerof the bridge a screw passes througl1,carrying at its end,P,a materialwhich will conduct electricity, and is c011- nected to one end of theprimary wire of an induction-coil, as illustrated in the diagram, Fig.3.

In Fig. 3, on each side of the center of the tympan T,are electrodes 0C,conncctcd to one pole of a battery, G. Opposite, very close to but nottouching either of the electrodes 0 G, are two electrodes, 1 I bothdircctl y con nected, or through the primary wire of an induction-coil,I, to the other pole of the same battery. It may sometimes occur thatthe elec- 5 trode C may get out of its proper adjustment and make aslight contact on the electrode P, or the electrode C may, from the samecause, make a slight contact on the electrode P. In either of thesecases the efficiency of the instrument is not impaired, because theimpact of the air-waves will instantly sever those contacts, and thetympan must continue its vibration in response to the vibrations of theairwaves, thus closing or opening or opening and closing the circuit.

In my present invention I make use of intermittent pulsations ofelectricity in contradistinction to undulatory currents of electricityfor the reproduction of vocal and other sounds, and I employ a methodand apparatus for causing makes and breaks in an electric circuit,whereby are sent into the circuit intermittent pulsations of electricityhaving all the qualities essential for the reproduction of vocal andother sounds.

For the reproduction of vocal and other sounds by means of electricity,it is not nec essary that there should be a continuity of an electriccurrent passing through a closed circuit connecting a transmitter with areceiver. All thatisnecessary is that theintermittent impulses ofelectricity which follow each other in the circuit should correspond innumber to that of the vibrations of the air which the voice has producedat the transmitting ends, that their varying intensities shouldcorrespond to the varying force of the vibration of the air, and thatthe intervals between them should be equal to the intervals between thevibrations of the air. Under these conditions, which are fulfilled by mymethod and apparatus,voca1 and other sounds in all their modificationscan be reproduced by an electromagnetic telephone-receiver placed in theelectric circuit.

It is obvious that the variations of the intensity of a continuouscurrent in a closed circuit are confined within a very narrow range andmust bear a very small proportion to the maximum intensity of theinitial current, whereas when intermittent pulsations of electricityaresent into a line the variations of the intensity of the current are themaximum variations. Consequently the variations of the magnetic force ofthe magnet of the telephonereceiver in the circuit are the maximumvariations. The air-waves on entering the case through the mouth-piecedo not fall at right angles upon the tympan, and therefore there do notoccur rebounds of the air, which materially interfere with the followingair-waves and prevent the tympan from vibrating in accord with theair-waves. In this apparatus the air-waves pass into the case nearlyparallel with the tympan, and as they reach the narrowest part of theair-chamber the density of the air is greatly increased, andconsequently the pressure of the air on the tympan is also greatlyincreased, and the tympan is forced against the opposite electrode, P.This contact is immediately severed by the united forces of kineticenergy of the rebound and of the pressure of the condensed air, andthese united forces press the tympan back beyond its normal position ofrest and cause it to make a contact on the electrode P. The movement ofthe tympan begins gradually and increases in force as the density of theair increases, and consequently the varying intensity of the electriccurrent is in proportion to the gradually increasing and decreasingpressure which the tympan makes upon the electrode. There is always aperiod during which a current upon closing a circuit increases inintensity, as there is a period of decreasing intensity upon opening acircuit. This varying intensity of the electric current produces uponthe magnet of the receiving-telephone variations of the magnetic forcecorresponding faith fully to the varying intensity ofthe electriccurrent.

It is advantageous to use an induced current in the line, and as theintensity of an induced current depends directly upon the rapidity,suddenness, and extent of the variations of the electric condition ofthe primary wire, it necessarily follows that intermittent impulses ofelectricity produce greater intensity in the induced currents than doundulatory currents.

In this application I do not claim, per se, the peculiar form of theair-chamber B B B B, because such a chamber was described and claimed inmy application filed January 18, 1886, Serial No. 188,813, and for whicha patent, No. 357,359, was issued on February 8, 1887; but

What I do claim as my present invention, and desire to secure by LettersPatent, is-

1. The combination, in a pneumatic instrument for sending intermittentimpulses of electricity into a conductor, of a tympan in a case havingan air-passage extending around the tympan, so that the air-waves willact first on one side of the tympan and afterward on the opposite sideof it, an electrode in the center of the tympan and at each side thereofconnected with one pole of a battery, and two electrodes connected withthe other pole of the same battery and placed opposite to each other andto the intervening electrode on the tympan.

2. The apparatus, substantially as herein described, for reproducingvocal and other sounds, consisting of a tympan, a case for containingthe same having an air-passage around the tympan, so that the air-waveswill act first on one side of the tympan and afterward on the oppositeside of it, an electrode in the center of the tympan connected with onepole of a battery, and two electrodes at opposite sides of theintervening electrode on the tympan, circuit-connections to suchelectrodes, a receiving telephonic instrument, and electriccircuit-connections through such receiving-instrument, substantially asspecified.

WILLIAM CHASE BARNEY.

Witnesses:

A. H. EVANS, D. S. CLARK.

